Electric medical appliance



March 12, 1940. G. THORNTON-NORRIS ,7

ELECTRIC MEDICAL APPLIANCE Filed Nov. 29, 19 57 v 2 Sheets-Sheet 1 March12, 1940. THORNTON-NORRIS 2,193,702

ELECTRIC MEDICAL APPLIANCE Filed NOV. 29. 1937 2 Sheets-Shet 2 PatentedMar. 12, 1940.

UNITED STATES PATENT OFFICE ELECTRIC MEDICAL APPLIANCE ApplicationNovember 29, 1937, Serial No. 177,085 In Great Britain November 30, 193610 Claims.

This invention relates to electric medical appliances adapted to applyelectric current to patients, for diagnostic or for curative purposesand it has reference, in particular, to appliances of this kind whereinat least one coil or solenoid in which the electric current is generatedis furnished with a movable core of magnetic material, which core, whenthe appliance is operating, is moved rhythmically by automatic drivingmeans and produces a corresponding change of the said current, thischange being known as surging. As is Well known, the surged current,when administered to a patient, will, if sufiiciently intense, producecorresponding contractions and extensions in the muscles affected.

The rate of surging and the duration of each surge of current areregulated by the frequency with which the movable magnetic core orsurger is introduced into and withdrawn from the coil, while the currentintensity can be varied by introducing the surger to a greater or lessextent.

It is an object of the present invention to provide an electric medicalappliance of the kind referred to wherein means are provided foraltering the characteristic form of the surged output current andthereby controlling the muscular reactions of the patient undertreatment.

A further object is to provide an apparatus of this kind which, when setin operation, will maintain with considerable accuracy any desiredperiodicity as well as any desired intensity of surging.

A still further object is to afford fine regulation of the intensity ofthe current applied to the patient.

Another object of the invention is to provide improved means for varyingthe rate and periodicity of surging within the useful limits of practiceand a more specific object is to provide for withdrawing the surgerfroml the coil faster than it is introduced thereinto or vice versa.

Yet another object of the invention is to provide manually operablemeans for finely graduated adjustment of the current generated in thecoil for any given position of the surger core. This last mentionedmeans may substitute but is preferably used to supplement the well knownlayer switch the contacts of which are severally connected to varioustapping points in the winding of the coil. Conveniently the said meansmay take the form of a variable resistance in circuit with the coilwindings: preferably in the primary or energising circuit of the coil.

In the accompanying drawings which show one embodiment of the invention;

Fig. 1 is a plan View of the control panel of an electric medicalappliance of the kind referred to and of a box-like casing for theappliance, the said casing being shown with a cover thrown open toexpose the panel.

Fig. 2 shows in frontal elevation, the panel and. the various membersmounted thereon, some directly and others indirectly.

Fig. 3 is a sectional plan View, the section be ing taken on lineIII-III of Fig. 2.

' Fig. 4 is a circuit diagram.

Referring firstly, to Fig. l, the control panel I of the appliance ismounted, as is usual, in a box-like casing 2 with a. lid or cover 3,hinged to it, as at 4. The panel carries on its upper side, the usualtrembler 5, mounted on a post 35, the contact screw 6 adjustable in apost 36, the actuating magnet I, with iron core 31, for driving thetrembler, the so-called patient terminals 8, to which various electrodesor applicators can be connected, and manual controls 9, l and H,hereinafter again referred to. The aforesaid trembler is provided withan armature 33 having a rod 34 carrying an adjustable damping Weight 38.

Part of the hollow cover 3 may be. partitioned off, as by a hingedpartition 12 and/or said cover may be furnished with one or more clipdevices, such as l3: in these ways accommodation is provided for storingelectrodes, applicators and flexible connections (including mainsconnections, as hereinafter referred to) when not in use.

Reference l4 (Figs. 2 and 3) designates a subpanel, supported bybrackets Hi from the main or exposed panel I. The induction coil orcurrent producing device comprises, in the example shown, two coilelements l6 arranged with their geometrical axes parallel and eachfurnished with a slidable iron core i l, constituting a surger. The twosurgers are coupled together by a yokepiece l8 carried slidably on a rod[9 which is fixed at 120 and at 52 so that its axis is parallel to theaxes of the coil elements it and their surgers Ill. The yoke I8 alsocarries a slotted lug 2|, the purpose of which will hereinafter appear.

A suitable operative drive for said surgers is provided by an electricmotor 22 mounted in this instance on the sub-panel M. As shown, saidmotor is below the said sub-panel and its shaft 23 projects through saidpanel and. has fixed to it a toothed pinion 24. The latter gears with aspur wheel 25 which is mounted rotatably on a stud 26 and is furnishedwith a crank pin 21. This crank pin, when the wheel 25 is rotated (bymotor 22, driving through pinion 24) Works to and fro along a slot 28 ina lever 29 pivoted at 30 and having, at its free end, a pin 31, adaptedto work in a slot 32 in the lug 2!. It will be perceived (see Fig. 3)that oscillation of the lever 29 by the crank pin 21 causes the yoke 18to slide on the rod l9, thereby reciprocating the surgers ll so that thelatter move into and out of the coil elements l6. Said crank pin 27, asit is moved around in a circular path, acts on the oscillating lever 29with an effect rendering it a continually changing lever arm, so that,according to the direction of rotation of the drive, either theintroducing strokeor the withdrawal stroke of the surgers relatively tothe coil elements can be made the more rapid. The motor 22 may be madereversible with the aid of a. simple reversing switch (not shown), orreversible transmission gearing (also not shown)-may be interposedbetween the motor and the surgers.

The periodicity of surging as well as the mean linear speed of movementof the surgers can be varied by varying the speed of the motor 22 withthe aid of an adjustable mechanical governor, as usually employed forcontrolling the speed of gramophone motors. A speed control shaft isindicated at 39 (Fig. 3). This shaft is rotatable through a limited arcby means of a slotted arm lll affixed to that end thereof whichprotrudes through and above the sub-panel i l. The knob l8 (Figs. 1 and2) controls a spindle ii on which are fixed a cam 42 and an arm 43, thelatter carrying a stud M engaging slidably with the slot 45 of theaforesaid arm 40 sothat turn of the spindle (by said knob) Will swingthe interlinked arms, as indicated by the dotted line positioningsthereof, to consequently turn or rotate the shaft 39 within its arclimits determined by the length of said arms. In this arrangement ofcourse the spindle. H and the shaft 39 are rotatable in oppositedirections. A switch 45 provides for opening and closing the operativedrive motor circuit. The aforementioned cam 42 is adapted to operatethis switch. Said cam has a flat surface portion ll which, in theposition shown in Fig. 3, allows the said switch to remain open, but anypart of the remaining arcuate surface 48 thereof will hold the switchclosed when the said cam is turned to an appropriate position by meansor" the knob l and spindle All. It will readily be seen that the arcuateportion 48 of the cam is operative over a considerable angular range ofrotation to keep the switch closed. Within this range the linkageprovided by the interconnected levers 43 and it is operable to adjustthe shaft 39 for varying degrees of motor speed adjustment by acting onthe governor setting. The arrangement illustrated is such that initialclockwise ro tation of the. cam 42 closes the switch 46, while furthermovement in the same direction gradually reduces the speed to which themotor is governed and, therefore, reduces the surging speed. The motoris stopped by rotating the cam 42 counter-clockwise, back to theposition shown in Fig. 3. Whereas, with this arrangement, motorstarting, stopping and speed regulation are under the control of one andthe same knob ill, it will be obvious that the starting and stoppingswitch may be actuated by a control which is independent of the controlused for varying the speed. Purely electrical'means of controlling thespeed of the surger actuating motor in apparatus of the kind referred tohas previously been suggested but in most cases I prefer to use amechanical control, as described, acting on a speed governor with africtional braking action as in ordinary gramophone motors.

A preferred arrangement of the electrical circuits is shown in Fig. 4.In this diagrammatic showing the surger coils Ill are depicted ascomprising primary windings- P (in series with the trembler magnet coil7, resistance battery 52 and trembler contacts 5, 5) and tappedsecondary windings S, the tapping points being several- 'ly connected tocontacts of the layer switch 50.

The coil circuits may be and preferably are quite separate from thecircuit of the surger actuating motor. The last named circuit, beingquite conventional, is, therefore, not included in Fig. 4. Ordinarilythe coil is battery driven, whereas the motor preferably takes powerfrom the mains, as, for instance, through suitable mains-connectingterminals 49 provided on the main panel I of the instrument. Theseterminals are shown as sockets adapted to receive a plug associated witha flexible connector (not shown) which connector, when not in use, canbe coiled up and lodged under the clip l3. A battery, feeding theprimary coil circuit, can be housed in the casing 2.

The said panel I also carries the usual so -called layer switch 56(Figs. 2 and 4) for varying the number of turns of coil windingsincluded in the secondary or patient circuit, the knob 9 serving foradjustment of this switch. The fine or Vernier manual adjustment whichconstitutes a further feature of the invention here takes the form of avariable resistance 5!, included in the primary or battery circuit ofthe coil (see Fig. l) to vary the strength of the primary currentderived from the battery 53.

The resistance fail is of a kind adapted for fine regulation and suchregulation is effected by means of the knob ii (Fig. 1). It is to beunderstood that for every position of the layer switch 5! a long rangeof finely variable adjustment of current strength can be obtained withthe additional control 5!. thermore this additional and fine controlpermits of adjusting primary current so as to obtain optimum action ofthe trembler blade 5 which, co-acting with the contact 6, makes andbreaks the primary coil circuit in the usual manner. Regular, that is tosay, non-erratic, trembler action is generally preferred and is favouredby careful adjustment of the primary current strength, as described.This additional control means can easily be arranged so that the primarycoil circuit is broken in one position. of the manipulating knob H and,finally, the latter can, in. case of need, be worked periodically byhand to produce a surging effect independently of the movable corealready referred to and of the motor for driving the said core. Thislatter possibility is extremely useful in event of failure of the motoror of its gearing to the movable core member or again, in cases wherepower for operating an electric. motor is not available. Naturally,nonelectric motors, such as clockwork or fluid driven motors may be usedfor operating the surger core, the motor starting and speed regulatingcontrol being appropriately modified as and Where necessary.

In particular, in the case of a non-electric motor, a mechanical lock(for clockwork) or a valve for fluid driven motors) would replace theswitch M5.

The arrangements described (which are portable and require no liquids)permit the current to be exactly regulated, as regards both intensityand rate of surging, to the particular patient or patients undertreatment. This can be done safely, particularly with the aid of thefine or Vernier control, while the patient is actually in the secondarycircuit and when the required conditions have once been established theycan be maintained indefinitely for as long as the treatment is requiredto continue, so that the operator whose duty it is to administer thesaid treatment is not compelled to watch its progress or perform anycontinuous manipulation but can give attention to other matters.

On the other hand, it is sometimes helpful for the operator to havevisual indication of the surger movement or of the position of thesurger at any given moment (other than such indication as is provided bythe muscular reactions of the patient or patients under treatment). Amechanical indicator such as a pointer or its equivalent, drivendirectly by the core structure or by some part of the transmissionmechanism may be used for this purpose, such pointer preferably workingin conjunction with a scale on the panel. Alternatively the indicatormay be arranged to signalise only the fully inserted position ofthecores, this being the position in which the aforementioned manuallycontrolled surging by means of the Vernier control is most effective.Both limiting positions of the reciprocating core structure may be thusindicated. Luminous indicating means (i. e. an electric lamp switched bythe moving surger mechanism.) may, of course be employed.

What I claim is:

1. In an electric medical appliance, a coil, means for generating anelectric current in said coil, means for delivering the current sogenerated, a magnetic body movable in. relation to said coil to vary thestrength of the current generated therein, a motor operatively connectedto said movable magnetic body to actuate the same and thereby to surgethe generated current and manually operable adjustable speed governingmeans co-actable mechanically with said motor for therethrough varyingthe rate and periodicity of the surging while the device is inoperation.

2. In an electric medical appliance: a coil, means for generating anelectric current in said coil, means for delivering the current sogenerated, a magnetic body movable in relation to said coil to vary thestrength of the current generated therein, a motor and transmissionmechanism operatively connecting said motor to said movable magneticbody to move the latter to and from said coil, said transmissionmechanism being organised to move said body towardssaid coil at a meanspeed difiering from the mean speed at which it moves said body awayfrom said coil.

3. The device of claim 2, characterised by means operable at will torender the mean speed of approximation of the movable magnetic body tothe coil greater than or less than the mean speed of retraction of saidbody from said coil.

4. The device of claim 2 including means acting mechanically on saidmotor to control the speed thereof and means including interlinkingswing arms operatively connected between said speed control means andseparate manually turnable means for adjusting said speed controllingmeans and maintaining the same in the adjusted position.

5. In an electric medical appliance; a coil, means for generating anelectric current in said coil, means for delivering the current sogenerated, a surger for the generated current, said surger comprising amagnetic core reciprocable into and out of said coil, power operatedrotary driving means, transmission means including a plurality of rotaryelements operatively interposed between said driving means and saidsurger and means for reversing the direction of rotation of the finalrotary element of said transmission means, the latter coacting with atransmission element which, according to the direction of rotation ofsaid final rotary element, determines whether the mean speed ofwithdrawal of the surger from the coil is greater or less than the meanspeed of introduction, of said surger into said coil.

6. In an electric medical appliance; a coil, means for generating anelectric current in said coil, means for delivering the current sogenerated, a surger for the generated current, said surger comprising amagnetic core reciprocable into and out of said coil, a motoroperatively associated with said surger to reciprocate the latter andcontrol means for said motor, said control means being adapted uponinitial movement from a terminal position, to start said motor and, uponfurther movement, to adjust a mechanical governor controlling the speedof said motor.

'7. A device according to claim 6, characterised by an electric drivingmotor, a starting switch for said motor and means such as a cam,actuated by the control means and operative to close said switch uponinitial movement of said control means.

8. In an electric medical appliance, a sectionalized coil having aprimary circuit including energising means and manually operable meansfor adjusting the degree of energisation and a secondary circuitassociated with means for including therein a variable number ofsections of the coil, for delivery therefrom of secondary current andautomatically operating means for surging the delivered secondarycurrent.

9. A device according to claim 8, and including variable means foradjusting the rate and periodicity of surging of the delivered secondarycurrent.

10. A device according to claim 8, including means for varying thecharacteristic form of the surged secondary current.

GEORGE THORNTON-NORRIS.

